package vn.codespot.hms.slidingmenu;

import java.util.ArrayList;
import java.util.Comparator;

import android.content.Context;
import android.content.res.TypedArray;
import android.database.DataSetObserver;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.os.Build;
import android.support.v4.view.KeyEventCompat;
import android.support.v4.view.MotionEventCompat;
import android.support.v4.view.VelocityTrackerCompat;
import android.support.v4.view.ViewCompat;
import android.support.v4.view.ViewConfigurationCompat;
import android.util.AttributeSet;
import android.util.Log;
import android.view.FocusFinder;
import android.view.Gravity;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.SoundEffectConstants;
import android.view.VelocityTracker;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.ViewGroup;
import android.view.ViewParent;
import android.view.accessibility.AccessibilityEvent;
import android.view.animation.Interpolator;
import android.widget.LinearLayout;
import android.widget.Scroller;

public class CustomViewAbove extends ViewGroup {
    private static final String TAG = "CustomViewAbove";
    private static final boolean DEBUG = false;

    private static final boolean USE_CACHE = false;

    private static final int MAX_SETTLE_DURATION = 600; // ms
    private static final int MIN_DISTANCE_FOR_FLING = 25; // dips

    private static final int[] LAYOUT_ATTRS = new int[] { android.R.attr.layout_gravity };

    static class ItemInfo {
        Object object;
        int position;
        boolean scrolling;
    }

    @SuppressWarnings("unused")
    private static final Comparator<ItemInfo> COMPARATOR = new Comparator<ItemInfo>() {

        public int compare(ItemInfo lhs, ItemInfo rhs) {
            return lhs.position - rhs.position;
        }
    };

    private static final Interpolator sInterpolator = new Interpolator() {
        public float getInterpolation(float t) {
            t -= 1.0f;
            return t * t * t * t * t + 1.0f;
        }
    };

    private ItemInfo mWindow;
    private ItemInfo mContent;

    private int mCurItem;
    private Scroller mScroller;

    private int mShadowWidth;
    private Drawable mShadowDrawable;
    private int mTopPageBounds;
    private int mBottomPageBounds;

    private int mChildWidthMeasureSpec;
    private int mChildHeightMeasureSpec;
    private boolean mInLayout;

    private boolean mScrollingCacheEnabled;

    private boolean mPopulatePending;
    private boolean mScrolling;

    private boolean mIsBeingDragged;
    private boolean mIsUnableToDrag;
    private int mTouchSlop;
    private float mInitialMotionX;
    /**
     * Position of the last motion event.
     */
    private float mLastMotionX;
    private float mLastMotionY;
    /**
     * ID of the active pointer. This is used to retain consistency during drags/flings if multiple pointers are used.
     */
    private int mActivePointerId = INVALID_POINTER;
    /**
     * Sentinel value for no current active pointer. Used by {@link #mActivePointerId}.
     */
    private static final int INVALID_POINTER = -1;

    /**
     * Determines speed during touch scrolling
     */
    private VelocityTracker mVelocityTracker;
    private int mMinimumVelocity;
    private int mMaximumVelocity;
    private int mFlingDistance;

    private boolean mFirstLayout = true;
    private boolean mCalledSuper;

    private boolean mLastTouchAllowed = false;
    private int mSlidingMenuThreshold = 10;
    private CustomViewBehind mCustomViewBehind2;
    private boolean mEnabled = true;

    private OnPageChangeListener mOnPageChangeListener;
    private OnPageChangeListener mInternalPageChangeListener;

    /**
     * Indicates that the pager is in an idle, settled state. The current page is fully in view and no animation is in progress.
     */
    public static final int SCROLL_STATE_IDLE = 0;

    /**
     * Indicates that the pager is currently being dragged by the user.
     */
    public static final int SCROLL_STATE_DRAGGING = 1;

    /**
     * Indicates that the pager is in the process of settling to a final position.
     */
    public static final int SCROLL_STATE_SETTLING = 2;

    private int mScrollState = SCROLL_STATE_IDLE;

    /**
     * Callback interface for responding to changing state of the selected page.
     */
    public interface OnPageChangeListener {

        /**
         * This method will be invoked when the current page is scrolled, either as part of a programmatically initiated smooth scroll or a
         * user initiated touch scroll.
         * 
         * @param position
         *            Position index of the first page currently being displayed. Page position+1 will be visible if positionOffset is
         *            nonzero.
         * @param positionOffset
         *            Value from [0, 1) indicating the offset from the page at position.
         * @param positionOffsetPixels
         *            Value in pixels indicating the offset from position.
         */
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels);

        /**
         * This method will be invoked when a new page becomes selected. Animation is not necessarily complete.
         * 
         * @param position
         *            Position index of the new selected page.
         */
        public void onPageSelected(int position);

        /**
         * Called when the scroll state changes. Useful for discovering when the user begins dragging, when the pager is automatically
         * settling to the current page, or when it is fully stopped/idle.
         * 
         * @param state
         *            The new scroll state.
         * @see CustomViewAbove#SCROLL_STATE_IDLE
         * @see CustomViewAbove#SCROLL_STATE_DRAGGING
         * @see CustomViewAbove#SCROLL_STATE_SETTLING
         */
        public void onPageScrollStateChanged(int state);
    }

    /**
     * Simple implementation of the {@link OnPageChangeListener} interface with stub implementations of each method. Extend this if you do
     * not intend to override every method of {@link OnPageChangeListener}.
     */
    public static class SimpleOnPageChangeListener implements OnPageChangeListener {

        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
            // This space for rent
        }

        public void onPageSelected(int position) {
            // This space for rent
        }

        public void onPageScrollStateChanged(int state) {
            // This space for rent
        }
    }

    /**
     * Used internally to tag special types of child views that should be added as pager decorations by default.
     */
    interface Decor {
    }

    public CustomViewAbove(Context context) {
        this(context, null);
    }

    public CustomViewAbove(Context context, AttributeSet attrs) {
        this(context, attrs, true);
    }

    public CustomViewAbove(Context context, AttributeSet attrs, boolean isAbove) {
        super(context, attrs);
        initCustomViewAbove(isAbove);
    }

    void initCustomViewAbove() {
        initCustomViewAbove(false);
    }

    void initCustomViewAbove(boolean isAbove) {
        setWillNotDraw(false);
        setDescendantFocusability(FOCUS_AFTER_DESCENDANTS);
        setFocusable(true);
        final Context context = getContext();
        mScroller = new Scroller(context, sInterpolator);
        final ViewConfiguration configuration = ViewConfiguration.get(context);
        mTouchSlop = ViewConfigurationCompat.getScaledPagingTouchSlop(configuration);
        mMinimumVelocity = configuration.getScaledMinimumFlingVelocity();
        mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();

        if (isAbove) {
            View v = new LinearLayout(getContext());
            v.setBackgroundResource(android.R.color.transparent);
            setMenu(v);
        }

        final float density = context.getResources().getDisplayMetrics().density;
        mFlingDistance = (int) (MIN_DISTANCE_FOR_FLING * density);
    }

    private void setScrollState(int newState) {
        if (mScrollState == newState) {
            return;
        }

        mScrollState = newState;
        if (mOnPageChangeListener != null) {
            mOnPageChangeListener.onPageScrollStateChanged(newState);
        }
    }

    @SuppressWarnings("unused")
    private void removeNonDecorViews() {
        for (int i = 0; i < getChildCount(); i++) {
            final View child = getChildAt(i);
            final LayoutParams lp = (LayoutParams) child.getLayoutParams();
            if (!lp.isDecor) {
                removeViewAt(i);
                i--;
            }
        }
    }

    /**
     * Set the currently selected page. If the CustomViewPager has already been through its first layout there will be a smooth animated
     * transition between the current item and the specified item.
     * 
     * @param item
     *            Item index to select
     */
    public void setCurrentItem(int item) {
        mPopulatePending = false;
        setCurrentItemInternal(item, !mFirstLayout, false);
    }

    /**
     * Set the currently selected page.
     * 
     * @param item
     *            Item index to select
     * @param smoothScroll
     *            True to smoothly scroll to the new item, false to transition immediately
     */
    public void setCurrentItem(int item, boolean smoothScroll) {
        mPopulatePending = false;
        setCurrentItemInternal(item, smoothScroll, false);
    }

    public int getCurrentItem() {
        return mCurItem;
    }

    void setCurrentItemInternal(int item, boolean smoothScroll, boolean always) {
        setCurrentItemInternal(item, smoothScroll, always, 0);
    }

    boolean isNull() {
        return mContent == null;
    }

    int getCount() {
        int count = 0;
        if (mWindow != null)
            count += 1;
        if (mContent != null)
            count += 1;
        return count;
    }

    void setCurrentItemInternal(int item, boolean smoothScroll, boolean always, int velocity) {
        if (isNull()) {
            setScrollingCacheEnabled(false);
            return;
        }
        if (!always && mCurItem == item && mWindow != null && mContent != null) {
            setScrollingCacheEnabled(false);
            return;
        }
        if (item < 0) {
            item = 0;
        } else if (item >= getCount()) {
            item = getCount() - 1;
        }
        if (item > 0 && item < getCount()) {
            // We are doing a jump by more than one page. To avoid
            // glitches, we want to keep all current pages in the view
            // until the scroll ends.
            mWindow.scrolling = true;
            mContent.scrolling = true;
        }
        final boolean dispatchSelected = mCurItem != item;
        mCurItem = item;
        populate();
        final int destX = getChildLeft(mCurItem);
        if (smoothScroll) {
            smoothScrollTo(destX, 0, velocity);
            if (dispatchSelected && mOnPageChangeListener != null) {
                mOnPageChangeListener.onPageSelected(item);
            }
            if (dispatchSelected && mInternalPageChangeListener != null) {
                mInternalPageChangeListener.onPageSelected(item);
            }
        } else {
            if (dispatchSelected && mOnPageChangeListener != null) {
                mOnPageChangeListener.onPageSelected(item);
            }
            if (dispatchSelected && mInternalPageChangeListener != null) {
                mInternalPageChangeListener.onPageSelected(item);
            }
            completeScroll();
            scrollTo(destX, 0);
        }
    }

    /**
     * Set a listener that will be invoked whenever the page changes or is incrementally scrolled. See {@link OnPageChangeListener}.
     * 
     * @param listener
     *            Listener to set
     */
    public void setOnPageChangeListener(OnPageChangeListener listener) {
        mOnPageChangeListener = listener;
    }

    /**
     * Set a separate OnPageChangeListener for internal use by the support library.
     * 
     * @param listener
     *            Listener to set
     * @return The old listener that was set, if any.
     */
    OnPageChangeListener setInternalPageChangeListener(OnPageChangeListener listener) {
        OnPageChangeListener oldListener = mInternalPageChangeListener;
        mInternalPageChangeListener = listener;
        return oldListener;
    }

    /**
     * Set the margin between pages.
     * 
     * @param shadowWidth
     *            Distance between adjacent pages in pixels
     * @see #getShadowWidth()
     * @see #setShadowDrawable(Drawable)
     * @see #setShadowDrawable(int)
     */
    @SuppressWarnings("unused")
    public void setShadowWidth(int shadowWidth) {
        final int oldWidth = mShadowWidth;
        mShadowWidth = shadowWidth;
        invalidate();
    }

    /**
     * Return the margin between pages.
     * 
     * @return The size of the margin in pixels
     */
    public int getShadowWidth() {
        return mShadowWidth;
    }

    /**
     * Set a drawable that will be used to fill the margin between pages.
     * 
     * @param d
     *            Drawable to display between pages
     */
    public void setShadowDrawable(Drawable d) {
        mShadowDrawable = d;
        if (d != null)
            refreshDrawableState();
        setWillNotDraw(d == null);
        invalidate();
    }

    /**
     * Set a drawable that will be used to fill the margin between pages.
     * 
     * @param resId
     *            Resource ID of a drawable to display between pages
     */
    public void setShadowDrawable(int resId) {
        setShadowDrawable(getContext().getResources().getDrawable(resId));
    }

    protected boolean verifyDrawable(Drawable who) {
        return super.verifyDrawable(who) || who == mShadowDrawable;
    }

    protected void drawableStateChanged() {
        super.drawableStateChanged();
        final Drawable d = mShadowDrawable;
        if (d != null && d.isStateful()) {
            d.setState(getDrawableState());
        }
    }

    // We want the duration of the page snap animation to be influenced by the distance that
    // the screen has to travel, however, we don't want this duration to be effected in a
    // purely linear fashion. Instead, we use this method to moderate the effect that the distance
    // of travel has on the overall snap duration.
    float distanceInfluenceForSnapDuration(float f) {
        f -= 0.5f; // center the values about 0.
        f *= 0.3f * Math.PI / 2.0f;
        return (float) Math.sin(f);
    }

    public int getDestScrollX() {
        if (isMenuOpen()) {
            return getBehindWidth();
        } else {
            return 0;
        }
    }

    public int getChildLeft(int i) {
        if (i <= 0)
            return 0;
        return getChildWidth(i - 1) + getChildLeft(i - 1);
    }

    public int getChildRight(int i) {
        return getChildLeft(i) + getChildWidth(i);
    }

    public boolean isMenuOpen() {
        return getCurrentItem() == 0;
    }

    public int getCustomWidth() {
        int i = isMenuOpen() ? 0 : 1;
        return getChildWidth(i);
    }

    public int getChildWidth(int i) {
        if (i <= 0) {
            return getBehindWidth();
        } else {
            return getChildAt(i).getMeasuredWidth();
        }
    }

    public int getBehindWidth() {
        if (mCustomViewBehind2 == null) {
            return 0;
        } else {
            return mCustomViewBehind2.getWidth();
        }
    }

    public boolean isSlidingEnabled() {
        return mEnabled;
    }

    public void setSlidingEnabled(boolean b) {
        mEnabled = b;
    }

    /**
     * Like {@link View#scrollBy}, but scroll smoothly instead of immediately.
     * 
     * @param x
     *            the number of pixels to scroll by on the X axis
     * @param y
     *            the number of pixels to scroll by on the Y axis
     */
    void smoothScrollTo(int x, int y) {
        smoothScrollTo(x, y, 0);
    }

    /**
     * Like {@link View#scrollBy}, but scroll smoothly instead of immediately.
     * 
     * @param x
     *            the number of pixels to scroll by on the X axis
     * @param y
     *            the number of pixels to scroll by on the Y axis
     * @param velocity
     *            the velocity associated with a fling, if applicable. (0 otherwise)
     */
    void smoothScrollTo(int x, int y, int velocity) {
        if (getChildCount() == 0) {
            // Nothing to do.
            setScrollingCacheEnabled(false);
            return;
        }
        int sx = getScrollX();
        int sy = getScrollY();
        int dx = x - sx;
        int dy = y - sy;
        if (dx == 0 && dy == 0) {
            completeScroll();
            setScrollState(SCROLL_STATE_IDLE);
            return;
        }

        setScrollingCacheEnabled(true);
        mScrolling = true;
        setScrollState(SCROLL_STATE_SETTLING);

        final int width = getCustomWidth();
        final int halfWidth = width / 2;
        final float distanceRatio = Math.min(1f, 1.0f * Math.abs(dx) / width);
        final float distance = halfWidth + halfWidth * distanceInfluenceForSnapDuration(distanceRatio);

        int duration = 0;
        velocity = Math.abs(velocity);
        if (velocity > 0) {
            duration = 4 * Math.round(1000 * Math.abs(distance / velocity));
        } else {
            final float pageDelta = (float) Math.abs(dx) / (width + mShadowWidth);
            duration = (int) ((pageDelta + 1) * 100);
            // TODO set custom duration!
            duration = MAX_SETTLE_DURATION;
        }
        duration = Math.min(duration, MAX_SETTLE_DURATION);

        mScroller.startScroll(sx, sy, dx, dy, duration);
        invalidate();
    }

    ArrayList<ItemInfo> getItems() {
        ArrayList<ItemInfo> mItems = new ArrayList<ItemInfo>();
        if (mWindow != null) {
            mItems.add(mWindow);
        }
        if (mContent != null) {
            mItems.add(mContent);
        }
        return mItems;
    }

    void dataSetChanged() {
        // This method only gets called if our observer is attached, so mAdapter is non-null.
        boolean needPopulate = false;
        int newCurrItem = -1;
        ArrayList<ItemInfo> items = getItems();
        for (int i = 0; i < items.size(); i++) {
            final ItemInfo ii = items.get(i);
            final int newPos = ii.position;

            if (ii.position != newPos) {
                if (ii.position == mCurItem) {
                    // Our current item changed position. Follow it.
                    newCurrItem = newPos;
                }

                ii.position = newPos;
                needPopulate = true;
            }
        }

        if (newCurrItem >= 0) {
            setCurrentItemInternal(newCurrItem, false, true);
            needPopulate = true;
        }
        if (needPopulate) {
            populate();
            requestLayout();
        }
    }

    @SuppressWarnings("unused")
    void populate() {
        // Bail now if we are waiting to populate. This is to hold off
        // on creating views from the time the user releases their finger to
        // fling to a new position until we have finished the scroll to
        // that position, avoiding glitches from happening at that point.
        if (mPopulatePending) {
            if (DEBUG)
                Log.i(TAG, "populate is pending, skipping for now...");
            return;
        }

        // Also, don't populate until we are attached to a window. This is to
        // avoid trying to populate before we have restored our view hierarchy
        // state and conflicting with what is restored.
        if (getWindowToken() == null) {
            return;
        }

        if (DEBUG) {
            Log.i(TAG, "Current page list:");
            for (int i = 0; i < getCount(); i++) {
                Log.i(TAG, "#" + i + ": page " + getItems().get(i).position);
            }
        }

        ItemInfo curItem = null;
        if (mWindow != null && mWindow.position == mCurItem) {
            curItem = mWindow;
        } else if (mContent != null && mContent.position == mCurItem) {
            curItem = mContent;
        }

        if (hasFocus()) {
            View currentFocused = findFocus();
            ItemInfo ii = currentFocused != null ? infoForAnyChild(currentFocused) : null;
            if (ii == null || ii.position != mCurItem) {
                for (int i = 0; i < getChildCount(); i++) {
                    View child = getChildAt(i);
                    ii = infoForChild(child);
                    if (ii != null && ii.position == mCurItem) {
                        if (child.requestFocus(FOCUS_FORWARD)) {
                            break;
                        }
                    }
                }
            }
        }
    }

    protected void setMenu(View v) {
        ItemInfo ii = new ItemInfo();
        ii.position = 0;
        ii.object = v;
        if (mWindow != null) {
            removeView((View) mWindow.object);
        }
        addView(v);
        mWindow = ii;
    }

    public void setContent(View v) {
        ItemInfo ii = new ItemInfo();
        ii.position = 1;
        ii.object = v;
        if (mContent != null) {
            removeView((View) mContent.object);
        }
        addView(v);
        mContent = ii;
    }

    public void setCustomViewBehind2(CustomViewBehind cvb) {
        mCustomViewBehind2 = cvb;
    }

    public void addView(View child, int index, ViewGroup.LayoutParams params) {
        if (!checkLayoutParams(params)) {
            params = generateLayoutParams(params);
        }
        final LayoutParams lp = (LayoutParams) params;
        lp.isDecor |= child instanceof Decor;
        if (mInLayout) {
            if (lp != null && lp.isDecor) {
                throw new IllegalStateException("Cannot add pager decor view during layout");
            }
            addViewInLayout(child, index, params);
            child.measure(mChildWidthMeasureSpec, mChildHeightMeasureSpec);
        } else {
            super.addView(child, index, params);
        }

        if (USE_CACHE) {
            if (child.getVisibility() != GONE) {
                child.setDrawingCacheEnabled(mScrollingCacheEnabled);
            } else {
                child.setDrawingCacheEnabled(false);
            }
        }
    }

    ItemInfo infoForChild(View child) {
        if (mWindow != null && child.equals(mWindow.object)) {
            return mWindow;
        } else if (mContent != null && child.equals(mContent.object)) {
            return mContent;
        }
        return null;
    }

    ItemInfo infoForAnyChild(View child) {
        ViewParent parent;
        while ((parent = child.getParent()) != this) {
            if (parent == null || !(parent instanceof View)) {
                return null;
            }
            child = (View) parent;
        }
        return infoForChild(child);
    }

    protected void onAttachedToWindow() {
        super.onAttachedToWindow();
        mFirstLayout = true;
    }

    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        // For simple implementation, or internal size is always 0.
        // We depend on the container to specify the layout size of
        // our view. We can't really know what it is since we will be
        // adding and removing different arbitrary views and do not
        // want the layout to change as this happens.
        int width = getDefaultSize(0, widthMeasureSpec);
        int height = getDefaultSize(0, heightMeasureSpec);
        setMeasuredDimension(width, height);

        // Children are just made to fill our space.
        int childWidthSize = getMeasuredWidth() - getPaddingLeft() - getPaddingRight();
        int childHeightSize = getMeasuredHeight() - getPaddingTop() - getPaddingBottom();

        /*
         * Make sure all children have been properly measured. Decor views first.
         * Right now we cheat and make this less complicated by assuming decor
         * views won't intersect. We will pin to edges based on gravity.
         */
        int size = getChildCount();
        for (int i = 0; i < size; ++i) {
            final View child = getChildAt(i);
            if (child.getVisibility() != GONE) {
                final LayoutParams lp = (LayoutParams) child.getLayoutParams();
                if (lp != null && lp.isDecor) {
                    final int hgrav = lp.gravity & Gravity.HORIZONTAL_GRAVITY_MASK;
                    final int vgrav = lp.gravity & Gravity.VERTICAL_GRAVITY_MASK;
                    if (DEBUG)
                        Log.d(TAG, "gravity: " + lp.gravity + " hgrav: " + hgrav + " vgrav: " + vgrav);
                    int widthMode = MeasureSpec.AT_MOST;
                    int heightMode = MeasureSpec.AT_MOST;
                    boolean consumeVertical = vgrav == Gravity.TOP || vgrav == Gravity.BOTTOM;
                    boolean consumeHorizontal = hgrav == Gravity.LEFT || hgrav == Gravity.RIGHT;

                    if (consumeVertical) {
                        widthMode = MeasureSpec.EXACTLY;
                    } else if (consumeHorizontal) {
                        heightMode = MeasureSpec.EXACTLY;
                    }
                    int pos = infoForChild(child).position;
                    childWidthSize = getChildWidth(pos);
                    final int widthSpec = MeasureSpec.makeMeasureSpec(childWidthSize, widthMode);
                    final int heightSpec = MeasureSpec.makeMeasureSpec(childHeightSize, heightMode);
                    child.measure(widthSpec, heightSpec);

                    if (consumeVertical) {
                        childHeightSize -= child.getMeasuredHeight();
                    } else if (consumeHorizontal) {
                        childWidthSize -= child.getMeasuredWidth();
                    }
                }
            }
        }

        mChildWidthMeasureSpec = MeasureSpec.makeMeasureSpec(childWidthSize, MeasureSpec.EXACTLY);
        mChildHeightMeasureSpec = MeasureSpec.makeMeasureSpec(childHeightSize, MeasureSpec.EXACTLY);

        // Make sure we have created all fragments that we need to have shown.
        mInLayout = true;
        populate();
        mInLayout = false;

        // Page views next.
        size = getChildCount();
        for (int i = 0; i < size; ++i) {
            final View child = getChildAt(i);
            if (child.getVisibility() != GONE) {
                if (DEBUG)
                    Log.v(TAG, "Measuring #" + i + " " + child + ": " + mChildWidthMeasureSpec);

                final LayoutParams lp = (LayoutParams) child.getLayoutParams();
                if (lp == null || !lp.isDecor) {
                    child.measure(mChildWidthMeasureSpec, mChildHeightMeasureSpec);
                }
            }
        }
    }

    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        // Make sure scroll position is set correctly.
        if (w != oldw) {
            recomputeScrollPosition(w, oldw, mShadowWidth, mShadowWidth);
        }
    }

    private void recomputeScrollPosition(int width, int oldWidth, int margin, int oldMargin) {
        final int widthWithMargin = width + margin;
        if (oldWidth > 0) {
            final int oldScrollPos = getDestScrollX();
            final int oldwwm = oldWidth + oldMargin;
            final int oldScrollItem = oldScrollPos / oldwwm;
            final float scrollOffset = (float) (oldScrollPos % oldwwm) / oldwwm;
            final int scrollPos = (int) ((oldScrollItem + scrollOffset) * widthWithMargin);
            scrollTo(scrollPos, getScrollY());
            if (!mScroller.isFinished()) {
                // We now return to your regularly scheduled scroll, already in progress.
                final int newDuration = mScroller.getDuration() - mScroller.timePassed();
                mScroller.startScroll(scrollPos, 0, getChildLeft(mCurItem), 0, newDuration);
            }
        } else {
            int scrollPos = getChildLeft(mCurItem);
            if (scrollPos != getScrollX()) {
                completeScroll();
                scrollTo(scrollPos, getScrollY());
            }
        }
    }

    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        mInLayout = true;
        populate();
        mInLayout = false;

        final int count = getChildCount();
        int height = b - t;
        int paddingTop = getPaddingTop();
        int paddingBottom = getPaddingBottom();

        for (int i = 0; i < count; i++) {
            final View child = getChildAt(i);
            if (child.getVisibility() != GONE) {
                int pos = infoForChild(child).position;
                int childLeft = 0;
                int childTop = 0;
                childLeft = getChildLeft(pos);
                child.layout(childLeft, childTop, childLeft + child.getMeasuredWidth(), childTop + child.getMeasuredHeight());
                if (DEBUG)
                    Log.v(TAG,
                            "top: " + childTop + ", left: " + childLeft + ", height: " + child.getMeasuredHeight() + ", width:"
                                    + child.getMeasuredWidth());
            }
        }
        mTopPageBounds = paddingTop;
        mBottomPageBounds = height - paddingBottom;
        mFirstLayout = false;
    }

    public void computeScroll() {
        if (DEBUG)
            Log.i(TAG, "computeScroll: finished=" + mScroller.isFinished());
        if (!mScroller.isFinished()) {
            if (mScroller.computeScrollOffset()) {
                if (DEBUG)
                    Log.i(TAG, "computeScroll: still scrolling");
                int oldX = getScrollX();
                int oldY = getScrollY();
                int x = mScroller.getCurrX();
                int y = mScroller.getCurrY();

                if (oldX != x || oldY != y) {
                    scrollTo(x, y);
                    pageScrolled(x);
                }

                // Keep on drawing until the animation has finished.
                invalidate();
                return;
            }
        }

        // Done with scroll, clean up state.
        completeScroll();
    }

    private void pageScrolled(int xpos) {
        // TODO
        final int widthWithMargin = getChildWidth(mCurItem) + mShadowWidth;
        final int position = xpos / widthWithMargin;
        final int offsetPixels = xpos % widthWithMargin;
        final float offset = (float) offsetPixels / widthWithMargin;

        mCalledSuper = false;
        onPageScrolled(position, offset, offsetPixels);
        if (!mCalledSuper) {
            throw new IllegalStateException("onPageScrolled did not call superclass implementation");
        }
    }

    /**
     * This method will be invoked when the current page is scrolled, either as part of a programmatically initiated smooth scroll or a user
     * initiated touch scroll. If you override this method you must call through to the superclass implementation (e.g.
     * super.onPageScrolled(position, offset, offsetPixels)) before onPageScrolled returns.
     * 
     * @param position
     *            Position index of the first page currently being displayed. Page position+1 will be visible if positionOffset is nonzero.
     * @param offset
     *            Value from [0, 1) indicating the offset from the page at position.
     * @param offsetPixels
     *            Value in pixels indicating the offset from position.
     */
    protected void onPageScrolled(int position, float offset, int offsetPixels) {
        if (mOnPageChangeListener != null) {
            mOnPageChangeListener.onPageScrolled(position, offset, offsetPixels);
        }
        if (mInternalPageChangeListener != null) {
            mInternalPageChangeListener.onPageScrolled(position, offset, offsetPixels);
        }
        mCalledSuper = true;
    }

    private void completeScroll() {
        boolean needPopulate = mScrolling;
        if (needPopulate) {
            // Done with scroll, no longer want to cache view drawing.
            setScrollingCacheEnabled(false);
            mScroller.abortAnimation();
            int oldX = getScrollX();
            int oldY = getScrollY();
            int x = mScroller.getCurrX();
            int y = mScroller.getCurrY();
            if (oldX != x || oldY != y) {
                scrollTo(x, y);
            }
            setScrollState(SCROLL_STATE_IDLE);
        }
        mPopulatePending = false;
        mScrolling = false;
        if (mWindow != null && mWindow.scrolling) {
            needPopulate = true;
            mWindow.scrolling = false;
        }
        if (mContent != null && mContent.scrolling) {
            needPopulate = true;
            mContent.scrolling = false;
        }
        if (needPopulate) {
            populate();
        }
    }

    private int mTouchModeAbove = SlidingMenu.TOUCHMODE_MARGIN;
    private int mTouchModeBehind = SlidingMenu.TOUCHMODE_MARGIN;

    public void setTouchModeAbove(int i) {
        mTouchModeAbove = i;
    }

    public int getTouchModeAbove() {
        return mTouchModeAbove;
    }

    public void setTouchModeBehind(int i) {
        mTouchModeBehind = i;
    }

    public int getTouchModeBehind() {
        return mTouchModeBehind;
    }

    private boolean thisTouchAllowed(MotionEvent ev) {
        if (isMenuOpen()) {
            switch (mTouchModeBehind) {
            case SlidingMenu.TOUCHMODE_FULLSCREEN:
                return true;
            case SlidingMenu.TOUCHMODE_MARGIN:
                return ev.getX() >= getBehindWidth() && ev.getX() <= getWidth();
            default:
                return false;
            }
        } else {
            switch (mTouchModeAbove) {
            case SlidingMenu.TOUCHMODE_FULLSCREEN:
                return true;
            case SlidingMenu.TOUCHMODE_MARGIN:
                return ev.getX() >= 0 && ev.getX() <= mSlidingMenuThreshold;
            default:
                return false;
            }
        }
    }

    public boolean onInterceptTouchEvent(MotionEvent ev) {
        /*
         * This method JUST determines whether we want to intercept the motion.
         * If we return true, onMotionEvent will be called and we do the actual
         * scrolling there.
         */

        if (!mEnabled) {
            return false;
        }

        if (!thisTouchAllowed(ev)) {
            return false;
        }

        final int action = ev.getAction() & MotionEventCompat.ACTION_MASK;

        // Always take care of the touch gesture being complete.
        if (action == MotionEvent.ACTION_CANCEL || action == MotionEvent.ACTION_UP) {
            // Release the drag.
            if (DEBUG)
                Log.v(TAG, "Intercept done!");
            mIsBeingDragged = false;
            mIsUnableToDrag = false;
            mActivePointerId = INVALID_POINTER;
            if (mVelocityTracker != null) {
                mVelocityTracker.recycle();
                mVelocityTracker = null;
            }
            return false;
        }

        // Nothing more to do here if we have decided whether or not we
        // are dragging.
        if (action != MotionEvent.ACTION_DOWN) {
            if (mIsBeingDragged) {
                if (DEBUG)
                    Log.v(TAG, "Intercept returning true!");
                return true;
            }
            if (mIsUnableToDrag) {
                if (DEBUG)
                    Log.v(TAG, "Intercept returning false!");
                return false;
            }
        }

        switch (action) {
        case MotionEvent.ACTION_MOVE: {
            /*
             * mIsBeingDragged == false, otherwise the shortcut would have caught it. Check
             * whether the user has moved far enough from his original down touch.
             */

            /*
             * Locally do absolute value. mLastMotionY is set to the y value
             * of the down event.
             */
            final int activePointerId = mActivePointerId;
            if (activePointerId == INVALID_POINTER) {
                // If we don't have a valid id, the touch down wasn't on content.
                break;
            }

            final int pointerIndex = MotionEventCompat.findPointerIndex(ev, activePointerId);
            final float x = MotionEventCompat.getX(ev, pointerIndex);
            final float dx = x - mLastMotionX;
            final float xDiff = Math.abs(dx);
            final float y = MotionEventCompat.getY(ev, pointerIndex);
            final float yDiff = Math.abs(y - mLastMotionY);
            if (DEBUG)
                Log.v(TAG, "Moved x to " + x + "," + y + " diff=" + xDiff + "," + yDiff);

            if (canScroll(this, false, (int) dx, (int) x, (int) y)) {
                // Nested view has scrollable area under this point. Let it be handled there.
                mInitialMotionX = mLastMotionX = x;
                mLastMotionY = y;
                return false;
            }
            if (xDiff > mTouchSlop && xDiff > yDiff) {
                if (DEBUG)
                    Log.v(TAG, "Starting drag!");
                mIsBeingDragged = true;
                setScrollState(SCROLL_STATE_DRAGGING);
                mLastMotionX = x;
                setScrollingCacheEnabled(true);
            } else {
                if (yDiff > mTouchSlop) {
                    // The finger has moved enough in the vertical
                    // direction to be counted as a drag... abort
                    // any attempt to drag horizontally, to work correctly
                    // with children that have scrolling containers.
                    if (DEBUG)
                        Log.v(TAG, "Starting unable to drag!");
                    mIsUnableToDrag = true;
                }
            }
            break;
        }

        case MotionEvent.ACTION_DOWN: {
            /*
             * Remember location of down touch.
             * ACTION_DOWN always refers to pointer index 0.
             */
            mLastMotionX = mInitialMotionX = ev.getX();
            mLastMotionY = ev.getY();
            mActivePointerId = MotionEventCompat.getPointerId(ev, 0);

            if (mScrollState == SCROLL_STATE_SETTLING) {
                // Let the user 'catch' the pager as it animates.
                mIsBeingDragged = true;
                mIsUnableToDrag = false;
                setScrollState(SCROLL_STATE_DRAGGING);
            } else if (isMenuOpen() || (mTouchModeAbove != SlidingMenu.TOUCHMODE_FULLSCREEN && thisTouchAllowed(ev))) {
                // we want to intercept this touch even though we are not dragging
                // so that we can close the menu on a touch
                mIsBeingDragged = false;
                mIsUnableToDrag = false;
                return true;
            } else {
                completeScroll();
                mIsBeingDragged = false;
                mIsUnableToDrag = false;
            }

            if (DEBUG)
                Log.v(TAG, "Down at " + mLastMotionX + "," + mLastMotionY + " mIsBeingDragged=" + mIsBeingDragged + "mIsUnableToDrag="
                        + mIsUnableToDrag);
            break;
        }

        case MotionEventCompat.ACTION_POINTER_UP:
            onSecondaryPointerUp(ev);
            break;
        }

        if (!mIsBeingDragged) {
            // Track the velocity as long as we aren't dragging.
            // Once we start a real drag we will track in onTouchEvent.
            if (mVelocityTracker == null) {
                mVelocityTracker = VelocityTracker.obtain();
            }
            mVelocityTracker.addMovement(ev);
        }

        /*
         * The only time we want to intercept motion events is if we are in the
         * drag mode.
         */
        return mIsBeingDragged;
    }

    public boolean onTouchEvent(MotionEvent ev) {
        if (!mEnabled) {
            return false;
        }

        if (!mLastTouchAllowed && !thisTouchAllowed(ev)) {
            return false;
        }

        final int action = ev.getAction();

        if (action == MotionEvent.ACTION_UP || action == MotionEvent.ACTION_POINTER_UP || action == MotionEvent.ACTION_CANCEL
                || action == MotionEvent.ACTION_OUTSIDE) {
            mLastTouchAllowed = false;
        } else {
            mLastTouchAllowed = true;
        }

        if (getCount() == 0) {
            // Nothing to present or scroll; nothing to touch.
            return false;
        }
        if (mVelocityTracker == null) {
            mVelocityTracker = VelocityTracker.obtain();
        }
        mVelocityTracker.addMovement(ev);

        switch (action & MotionEventCompat.ACTION_MASK) {
        case MotionEvent.ACTION_DOWN: {
            /*
             * If being flinged and user touches, stop the fling. isFinished
             * will be false if being flinged.
             */
            completeScroll();

            // Remember where the motion event started
            mLastMotionX = mInitialMotionX = ev.getX();
            mActivePointerId = MotionEventCompat.getPointerId(ev, 0);
            break;
        }
        case MotionEvent.ACTION_MOVE:
            if (!mIsBeingDragged) {
                final int pointerIndex = MotionEventCompat.findPointerIndex(ev, mActivePointerId);
                final float x = MotionEventCompat.getX(ev, pointerIndex);
                final float xDiff = Math.abs(x - mLastMotionX);
                final float y = MotionEventCompat.getY(ev, pointerIndex);
                final float yDiff = Math.abs(y - mLastMotionY);
                if (DEBUG)
                    Log.v(TAG, "Moved x to " + x + "," + y + " diff=" + xDiff + "," + yDiff);
                if (xDiff > mTouchSlop && xDiff > yDiff) {
                    if (DEBUG)
                        Log.v(TAG, "Starting drag!");
                    mIsBeingDragged = true;
                    mLastMotionX = x;
                    setScrollState(SCROLL_STATE_DRAGGING);
                    setScrollingCacheEnabled(true);
                }
            }
            if (mIsBeingDragged) {
                // Scroll to follow the motion event
                final int activePointerIndex = MotionEventCompat.findPointerIndex(ev, mActivePointerId);
                final float x = MotionEventCompat.getX(ev, activePointerIndex);
                final float deltaX = mLastMotionX - x;
                mLastMotionX = x;
                float oldScrollX = getScrollX();
                float scrollX = oldScrollX + deltaX;
                // TODO
                final float leftBound = 0;
                final float rightBound = getBehindWidth();
                if (scrollX < leftBound) {
                    scrollX = leftBound;
                } else if (scrollX > rightBound) {
                    scrollX = rightBound;
                }
                // Don't lose the rounded component
                mLastMotionX += scrollX - (int) scrollX;
                scrollTo((int) scrollX, getScrollY());
                pageScrolled((int) scrollX);
            }
            break;
        case MotionEvent.ACTION_UP:
            if (mIsBeingDragged) {
                final VelocityTracker velocityTracker = mVelocityTracker;
                velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
                int initialVelocity = (int) VelocityTrackerCompat.getXVelocity(velocityTracker, mActivePointerId);
                mPopulatePending = true;
                final int widthWithMargin = getChildWidth(mCurItem) + mShadowWidth;
                final int scrollX = getScrollX();
                final int currentPage = scrollX / widthWithMargin;
                final float pageOffset = (float) (scrollX % widthWithMargin) / widthWithMargin;
                final int activePointerIndex = MotionEventCompat.findPointerIndex(ev, mActivePointerId);
                final float x = MotionEventCompat.getX(ev, activePointerIndex);
                final int totalDelta = (int) (x - mInitialMotionX);
                int nextPage = determineTargetPage(currentPage, pageOffset, initialVelocity, totalDelta);
                setCurrentItemInternal(nextPage, true, true, initialVelocity);

                mActivePointerId = INVALID_POINTER;
                endDrag();
            } else if (isMenuOpen()) {
                // close the menu
                setCurrentItem(1);
            }
            break;
        case MotionEvent.ACTION_CANCEL:
            if (mIsBeingDragged) {
                setCurrentItemInternal(mCurItem, true, true);
                mActivePointerId = INVALID_POINTER;
                endDrag();
            }
            break;
        case MotionEventCompat.ACTION_POINTER_DOWN: {
            final int index = MotionEventCompat.getActionIndex(ev);
            final float x = MotionEventCompat.getX(ev, index);
            mLastMotionX = x;
            mActivePointerId = MotionEventCompat.getPointerId(ev, index);
            break;
        }
        case MotionEventCompat.ACTION_POINTER_UP:
            onSecondaryPointerUp(ev);
            mLastMotionX = MotionEventCompat.getX(ev, MotionEventCompat.findPointerIndex(ev, mActivePointerId));
            break;
        }
        return true;
    }

    private float mScrollScale;

    public float getScrollScale() {
        return mScrollScale;
    }

    public void setScrollScale(float f) {
        if (f >= 0 && f <= 1) {
            mScrollScale = f;
        }
    }

    @Override
    public void scrollTo(int x, int y) {
        super.scrollTo(x, y);
        if (mCustomViewBehind2 != null && mEnabled) {
            mCustomViewBehind2.scrollTo((int) (x * mScrollScale), y);
        }
        invalidate();
    }

    private int determineTargetPage(int currentPage, float pageOffset, int velocity, int deltaX) {
        int targetPage;
        if (Math.abs(deltaX) > mFlingDistance && Math.abs(velocity) > mMinimumVelocity) {
            targetPage = velocity > 0 ? currentPage : currentPage + 1;
        } else {
            targetPage = (int) (currentPage + pageOffset + 0.5f);
        }
        return targetPage;
    }

    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        final int behindWidth = getBehindWidth();
        // Draw the margin drawable if needed.
        if (mShadowWidth > 0 && mShadowDrawable != null) {
            final int left = behindWidth - mShadowWidth;
            mShadowDrawable.setBounds(left, mTopPageBounds, left + mShadowWidth, mBottomPageBounds);
            mShadowDrawable.draw(canvas);
        }

        // if (mFadeEnabled) {
        // float openPercent = 0;
        // if (mScrollState == SCROLL_STATE_DRAGGING) {
        // openPercent= (behindWidth - Math.min(mLastMotionX, behindWidth)) / (float) behindWidth;
        // Log.v("STATE_DRAGGING", "openPercent: "+openPercent);
        // } else {
        // openPercent= (mScroller.getCurrX()) / (float) behindWidth;
        // Log.v("STATE_SETTLING", "openPercent: "+openPercent+", scrollerX: "+mScroller.getCurrX());
        // }
        // onDrawBehindFade(canvas, openPercent, behindWidth);
        // }
    }

    private float mFadeDegree;
    private Paint mBehindFadePaint = new Paint();
    @SuppressWarnings("unused")
    private boolean mFadeEnabled;

    @SuppressWarnings("unused")
    private void onDrawBehindFade(Canvas canvas, float openPercent, int width) {
        final int alpha = (int) (mFadeDegree * 255 * openPercent);

        if (alpha > 0) {
            mBehindFadePaint.setColor(Color.argb(alpha, 0, 0, 0));
            canvas.drawRect(0, 0, width, getHeight(), mBehindFadePaint);
        }
    }

    public void setBehindFadeEnabled(boolean b) {
        mFadeEnabled = b;
    }

    public void setBehindFadeDegree(float f) {
        mFadeDegree = f;
    }

    private void onSecondaryPointerUp(MotionEvent ev) {
        final int pointerIndex = MotionEventCompat.getActionIndex(ev);
        final int pointerId = MotionEventCompat.getPointerId(ev, pointerIndex);
        if (pointerId == mActivePointerId) {
            // This was our active pointer going up. Choose a new
            // active pointer and adjust accordingly.
            final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
            mLastMotionX = MotionEventCompat.getX(ev, newPointerIndex);
            mActivePointerId = MotionEventCompat.getPointerId(ev, newPointerIndex);
            if (mVelocityTracker != null) {
                mVelocityTracker.clear();
            }
        }
    }

    private void endDrag() {
        mIsBeingDragged = false;
        mIsUnableToDrag = false;

        if (mVelocityTracker != null) {
            mVelocityTracker.recycle();
            mVelocityTracker = null;
        }
    }

    private void setScrollingCacheEnabled(boolean enabled) {
        if (mScrollingCacheEnabled != enabled) {
            mScrollingCacheEnabled = enabled;
            if (USE_CACHE) {
                final int size = getChildCount();
                for (int i = 0; i < size; ++i) {
                    final View child = getChildAt(i);
                    if (child.getVisibility() != GONE) {
                        child.setDrawingCacheEnabled(enabled);
                    }
                }
            }
        }
    }

    /**
     * Tests scrollability within child views of v given a delta of dx.
     * 
     * @param v
     *            View to test for horizontal scrollability
     * @param checkV
     *            Whether the view v passed should itself be checked for scrollability (true), or just its children (false).
     * @param dx
     *            Delta scrolled in pixels
     * @param x
     *            X coordinate of the active touch point
     * @param y
     *            Y coordinate of the active touch point
     * @return true if child views of v can be scrolled by delta of dx.
     */
    protected boolean canScroll(View v, boolean checkV, int dx, int x, int y) {
        if (v instanceof ViewGroup) {
            final ViewGroup group = (ViewGroup) v;
            final int scrollX = v.getScrollX();
            final int scrollY = v.getScrollY();
            final int count = group.getChildCount();
            // Count backwards - let topmost views consume scroll distance first.
            for (int i = count - 1; i >= 0; i--) {
                // TODO: Add versioned support here for transformed views.
                // This will not work for transformed views in Honeycomb+
                final View child = group.getChildAt(i);
                if (x + scrollX >= child.getLeft() && x + scrollX < child.getRight() && y + scrollY >= child.getTop()
                        && y + scrollY < child.getBottom()
                        && canScroll(child, true, dx, x + scrollX - child.getLeft(), y + scrollY - child.getTop())) {
                    return true;
                }
            }
        }

        return checkV && ViewCompat.canScrollHorizontally(v, -dx);
    }

    public boolean dispatchKeyEvent(KeyEvent event) {
        // Let the focused view and/or our descendants get the key first
        return super.dispatchKeyEvent(event) || executeKeyEvent(event);
    }

    /**
     * You can call this function yourself to have the scroll view perform scrolling from a key event, just as if the event had been
     * dispatched to it by the view hierarchy.
     * 
     * @param event
     *            The key event to execute.
     * @return Return true if the event was handled, else false.
     */
    public boolean executeKeyEvent(KeyEvent event) {
        boolean handled = false;
        if (event.getAction() == KeyEvent.ACTION_DOWN) {
            switch (event.getKeyCode()) {
            case KeyEvent.KEYCODE_DPAD_LEFT:
                handled = arrowScroll(FOCUS_LEFT);
                break;
            case KeyEvent.KEYCODE_DPAD_RIGHT:
                handled = arrowScroll(FOCUS_RIGHT);
                break;
            case KeyEvent.KEYCODE_TAB:
                if (Build.VERSION.SDK_INT >= 11) {
                    // The focus finder had a bug handling FOCUS_FORWARD and FOCUS_BACKWARD
                    // before Android 3.0. Ignore the tab key on those devices.
                    if (KeyEventCompat.hasNoModifiers(event)) {
                        handled = arrowScroll(FOCUS_FORWARD);
                    } else if (KeyEventCompat.hasModifiers(event, KeyEvent.META_SHIFT_ON)) {
                        handled = arrowScroll(FOCUS_BACKWARD);
                    }
                }
                break;
            }
        }
        return handled;
    }

    public boolean arrowScroll(int direction) {
        View currentFocused = findFocus();
        if (currentFocused == this)
            currentFocused = null;

        boolean handled = false;

        View nextFocused = FocusFinder.getInstance().findNextFocus(this, currentFocused, direction);
        if (nextFocused != null && nextFocused != currentFocused) {
            if (direction == View.FOCUS_LEFT) {
                // If there is nothing to the left, or this is causing us to
                // jump to the right, then what we really want to do is page left.
                if (currentFocused != null && nextFocused.getLeft() >= currentFocused.getLeft()) {
                    handled = pageLeft();
                } else {
                    handled = nextFocused.requestFocus();
                }
            } else if (direction == View.FOCUS_RIGHT) {
                // If there is nothing to the right, or this is causing us to
                // jump to the left, then what we really want to do is page right.
                if (currentFocused != null && nextFocused.getLeft() <= currentFocused.getLeft()) {
                    handled = pageRight();
                } else {
                    handled = nextFocused.requestFocus();
                }
            }
        } else if (direction == FOCUS_LEFT || direction == FOCUS_BACKWARD) {
            // Trying to move left and nothing there; try to page.
            handled = pageLeft();
        } else if (direction == FOCUS_RIGHT || direction == FOCUS_FORWARD) {
            // Trying to move right and nothing there; try to page.
            handled = pageRight();
        }
        if (handled) {
            playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction));
        }
        return handled;
    }

    boolean pageLeft() {
        if (mCurItem > 0) {
            setCurrentItem(mCurItem - 1, true);
            return true;
        }
        return false;
    }

    boolean pageRight() {
        if (mCurItem < (getCount() - 1)) {
            setCurrentItem(mCurItem + 1, true);
            return true;
        }
        return false;
    }

    /**
     * We only want the current page that is being shown to be focusable.
     */

    public void addFocusables(ArrayList<View> views, int direction, int focusableMode) {
        final int focusableCount = views.size();

        final int descendantFocusability = getDescendantFocusability();

        if (descendantFocusability != FOCUS_BLOCK_DESCENDANTS) {
            for (int i = 0; i < getChildCount(); i++) {
                final View child = getChildAt(i);
                if (child.getVisibility() == VISIBLE) {
                    ItemInfo ii = infoForChild(child);
                    if (ii != null && ii.position == mCurItem) {
                        child.addFocusables(views, direction, focusableMode);
                    }
                }
            }
        }

        // we add ourselves (if focusable) in all cases except for when we are
        // FOCUS_AFTER_DESCENDANTS and there are some descendants focusable. this is
        // to avoid the focus search finding layouts when a more precise search
        // among the focusable children would be more interesting.
        if (descendantFocusability != FOCUS_AFTER_DESCENDANTS ||
        // No focusable descendants
                (focusableCount == views.size())) {
            // Note that we can't call the superclass here, because it will
            // add all views in. So we need to do the same thing View does.
            if (!isFocusable()) {
                return;
            }
            if ((focusableMode & FOCUSABLES_TOUCH_MODE) == FOCUSABLES_TOUCH_MODE && isInTouchMode() && !isFocusableInTouchMode()) {
                return;
            }
            if (views != null) {
                views.add(this);
            }
        }
    }

    /**
     * We only want the current page that is being shown to be touchable.
     */

    public void addTouchables(ArrayList<View> views) {
        // Note that we don't call super.addTouchables(), which means that
        // we don't call View.addTouchables(). This is okay because a CustomViewPager
        // is itself not touchable.
        for (int i = 0; i < getChildCount(); i++) {
            final View child = getChildAt(i);
            if (child.getVisibility() == VISIBLE) {
                ItemInfo ii = infoForChild(child);
                if (ii != null && ii.position == mCurItem) {
                    child.addTouchables(views);
                }
            }
        }
    }

    /**
     * We only want the current page that is being shown to be focusable.
     */

    protected boolean onRequestFocusInDescendants(int direction, Rect previouslyFocusedRect) {
        int index;
        int increment;
        int end;
        int count = getChildCount();
        if ((direction & FOCUS_FORWARD) != 0) {
            index = 0;
            increment = 1;
            end = count;
        } else {
            index = count - 1;
            increment = -1;
            end = -1;
        }
        for (int i = index; i != end; i += increment) {
            View child = getChildAt(i);
            if (child.getVisibility() == VISIBLE) {
                ItemInfo ii = infoForChild(child);
                if (ii != null && ii.position == mCurItem) {
                    if (child.requestFocus(direction, previouslyFocusedRect)) {
                        return true;
                    }
                }
            }
        }
        return false;
    }

    public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) {
        // CustomViewPagers should only report accessibility info for the current page,
        // otherwise things get very confusing.

        // TODO: Should this note something about the paging container?

        final int childCount = getChildCount();
        for (int i = 0; i < childCount; i++) {
            final View child = getChildAt(i);
            if (child.getVisibility() == VISIBLE) {
                final ItemInfo ii = infoForChild(child);
                if (ii != null && ii.position == mCurItem && child.dispatchPopulateAccessibilityEvent(event)) {
                    return true;
                }
            }
        }

        return false;
    }

    protected ViewGroup.LayoutParams generateDefaultLayoutParams() {
        return new LayoutParams();
    }

    protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) {
        return generateDefaultLayoutParams();
    }

    protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
        return p instanceof LayoutParams && super.checkLayoutParams(p);
    }

    public ViewGroup.LayoutParams generateLayoutParams(AttributeSet attrs) {
        return new LayoutParams(getContext(), attrs);
    }

    @SuppressWarnings("unused")
    private class PagerObserver extends DataSetObserver {

        public void onChanged() {
            dataSetChanged();
        }

        public void onInvalidated() {
            dataSetChanged();
        }
    }

    /**
     * Layout parameters that should be supplied for views added to a CustomViewPager.
     */
    public static class LayoutParams extends ViewGroup.LayoutParams {
        /**
         * true if this view is a decoration on the pager itself and not a view supplied by the adapter.
         */
        public boolean isDecor;

        /**
         * Where to position the view page within the overall CustomViewPager container; constants are defined in
         * {@link android.view.Gravity}.
         */
        public int gravity;

        public LayoutParams() {
            this(-1);
        }

        public LayoutParams(int customWidth) {
            super(FILL_PARENT, FILL_PARENT);
            if (customWidth >= 0) {
                width = customWidth;
            }
        }

        public LayoutParams(Context context, AttributeSet attrs) {
            super(context, attrs);

            final TypedArray a = context.obtainStyledAttributes(attrs, LAYOUT_ATTRS);
            gravity = a.getInteger(0, Gravity.NO_GRAVITY);
            a.recycle();
        }
    }
}
